When Kano, Natural Plant's second [Constant] is triggered while she is protected by this ARTS, Kano's second [Constant] will still be activated.
In this case, Kano will not be able to banish herself, but will banish the opponent's SIGNI. Kano's [Constant] conditions are still met, therefore she will trigger and activate again, still being unable to banish herself, but will banish the opponent's SIGNI. In the end, until the abilities expire, Kano will continuously banish all of your opponent's SIGNI.
In the case of Kanobanishing herself endlessly, advance the game as normal.